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1

Utilizing Taguchi Method and Regression Analysis for Optimizing Sand Mould Flowability

Abdulamer Dheya, Muhsan Ali A., Hamdi Sinan S.

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 3

5--9

EN

Parameters of the moulding process in foundry are usually determined by trial-and-error method, and this way contributes to time taken and adds further cost for production sand. The present work represents an attempt to optimize sand moulding parameters in terms of compactability, compaction time, and air pressure, and to study effect of these factors on the green sand flowability using L4 design of experiments. Regression model, Taguchi method, and experimental verification were used to investigate flow property of sodium bentonite- bonded BP-quartz sand for sand moulding. Analysis of variance (ANOVA) was employed to measure significance and contributions of different moulding variables on flowability of green sand. The values obtained showed that the compaction time factor significantly affected flowability of green sand while compactability and air pressure have slight effects. The comparison results of Taguchi method, regression predictions and experiments exhibited good agreement.

2

The Comparison of Chosen - Bonded with the Use of Classical and Dedicated for 3D Printing Furfuryl Binder - Molding Sands’ Properties as a Basis for Development a New Inorganic System

Halejcio D. M., Major-Gabryś K. A.

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 4

49--55

EN

Binder jetting technology (3D printing) in the production of foundry molds and cores is becoming more and more industrially used due to ensuring very good quality of the casting surface. In 3D printing technology as the matrix, quartz sand is mainly used, with a grain size of 0.14-0.25 mm. The binder is an organic binder - most often furfuryl resins. As part of this work, self-hardening molding sands with furfuryl resins dedicated to the classic production of molds and cores, as well as molding sands with resin dedicated to 3D printing, were tested. The aim of the research was to compare the viscosity of binders and the properties of molding sands prepared based on binding systems both dedicated to the classic production of molds and cores and for 3D printing. Tests were carried out on the binding kinetics, bench life, strength properties, permeability, abrasion and hot distortion of molding sands prepared on the basis of a standard medium grain matrix and sieved fine-grain matrix. The carried-out tests have shown that the binding system based on furfuryl resin elaborated for 3D printing of molding sands provides strength properties of the sands similar to the classic system of binding self-hardening molding sands with furfuryl resins. However, it ensures faster binding speed and greater thermal stability measured by the hot distortion parameter. The use of a fine-grained matrix results in a decrease in the strength properties of all the molding sands. On the basis of the results achieved for molding sands with organic binding system, a new inorganic binding system was elaborated.

3

Quality Assessment Method for Chromite Sand to Reduce the Number of Cast Steel Surface Defects

Wróbel Tomasz, Jezierski J., Bartocha D., Feliks E., Paleń A.

Archives of Foundry Engineering

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2024

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Vol. 24, iss. 4

31--38

EN

This paper discusses the ability to apply the test method using a scanning electron microscope (SEM) together with EDS (Energy Dispersive Spectroscopy) analysis to assess the quality of fresh chromite sand delivered by various suppliers to Huta Małapanew Sp. z o.o. The research was initiated due to the non-cyclical occurrence of surface casting defects, i.e. pitted skin and burn-on of chromite moulding sand for cast steel casting. The scope of studies comprised the quality assessment of sixteen chromite sand batches delivered for six months by two suppliers. The analysis of the results obtained was used to describe components of the tested chromite sand batches and develop criteria for their quality assessment, considering the chemical composition of chromite grains and the amount of impurities in the form of silica sand and the binder particles. Moreover, clear suggestions were developed concerning the ability to use the given chromite sand batch as the base of moulding sand made in Alphaset technology in Huta Małapanew Sp. z o.o.

4

Impact of the Different Moulding Parameters on Properties of the Green Sand Mould

Abdulamer Dheya

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 2

5--9

EN

Sand Casting process depends mainly on properties of the green sand mould, sand casting requires producing green sand mould without failure and breakage during separation the mould from the model, transportation and handling. Production of the green sand mould corresponding to dimensions and form of the desired model without troubles depends on the properties of the green sand. Ratio of constituents, preparation method of the green sand, mixing and pressing processes determine properties of green sand. In the present work, study effect of the moulding parameters of bentonite content, mixing time, and compactability percentage on the properties of the green sand mould have been investigated. Design of experiments through Taguchi method was used to evaluate properties of permeability, compressive strength, and tensile strength of the green sand. It was found that 47% of compactability, 9(min) of mixing time, and 6% of bentonite content gives highest values of these properties simultaneously.

5

Evaluation of Mixing Efficiency and How it Affects the Properties of the New Green Sand Mixtures

Kielar Šimon, Bašistová Martina, Lichý Petr

Archives of Foundry Engineering

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2023

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Vol. 23, iss. 3

88--93

EN

The current trend in the preparation of green sand mixtures emphasizes the acceleration of the mixing process while maintaining the quality of the mixture. This requirement results in the necessity of determining the optimal conditions for mixing the mixture with a given mixer. This work aims to determine the optimal mixing conditions for the newly introduced eddy mixer LM-3e from the company Multiserw-Morek in the sand laboratory at the Department of Metallurgical Technologies, Faculty of Materials and Technology, VŠB - Technical University of Ostrava. The main monitored properties of mixtures will be green compressive strength and moisture of the mixture. The measured properties of the mixture mixed on the eddy mixer will be compared with the properties of the mixture mixed on the existing LM-2e wheel mixer. The result of the experiment confirmed that the eddy mixer is suitable for the preparation of a mixture of the same quality as the wheel mixer but with a significantly reduced mixing time.

6

Studies of mechanical and technological parameters and evaluation of the role of lustrous carbon carriers in green moulding sands with hybrid bentonite

Kamińska Jadwiga, Stachowicz Mateusz, Puzio Sabina, Angrecki Michał

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e11, 2023

EN

Green moulding sands containing special carbonaceous additives, which are the source of lustrous carbon (LC), are discussed in this paper. Five potential lustrous carbon carriers, i.e., two types of hard coal dust (No.1 and No.2), amorphous graphite (No.3) and two hydrocarbon resins (No.4 and No.5), were selected for tests as carbonaceous additives to conventional moulding sands. To better emphasize the differences in the additives used, reference green moulding sand (GMS1) was prepared and subjected to a wide range of basic tests focussed on technological parameters, such as permeability (Pw), friability (Fw), Dietert mouldability test (PD) and compactability (Z) and mechanical parameters, such as compressive strength (Rcw), tensile strength (Rmw), strength in the transformation zone (Rkw). The proposed comprehensive spectrum of tests was repeated on sands with five carbonaceous additives. The most important for the use of additives as carbon carriers was to interrelate the content of lustrous carbon (LC), loss on ignition (LOI) and the obtained results of mechanical and technological tests carried out on conventional moulding sands with the surface quality of iron castings. For this purpose, a series of iron castings was made in the prepared moulding sands and used for the assessment of surface quality based on a number of roughness parameters (Ra, Rz, Rp, Rq, Rv, Rlr, RSm). As a result of the studies it was found that the carbonaceous additives proposed for use help to obtain high-quality surfaces in iron castings.

7

The Effect of Reclaim Primary Quality on Moulding Sand Parameters and Quality of Ductile Iron Casting Surface Layer

Kamińska Jadwiga, Angrecki M., Puzio S., Stachowicz M.

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 2

83--88

EN

The aim of the research was to determine the effect of the primary quality of reclaim from dry mechanical reclamation on the strength properties and service life of moulding sands based on this reclaim. Another aim was to establish the effect of the quality of reclaim, sulphur content - in particular, on the surface quality and thickness of the deformed surface layer in ductile iron castings. The research has revealed differences in the strength parameters and service life (mouldability) of sands based on the tested reclaims, depending on the type of the furfuryl resin used, including resins whose synthesis was done as part of the Żywfur project. Examinations of the structure of the surface layer of test castings poured in moulds made of loose self-hardening sands containing the addition of reclaim have confirmed the occurrence of degenerated spheroidal graphite in this part of the casting. It should be noted here that when massive castings with a long solidification time are made, the graphite degeneration effect can be more visible and the layer with the changed structure can increase in thickness. The research has clearly shown that it is necessary to control the parameters of the reclaim, including sulphur content which is transferred from the hardener and accumulates on the grains. This phenomenon has a negative impact not only on the sand strength and technological properties but also on the surface layer of castings.

8

Influence of Sawdust Ash Addition on Molding Sand Properties and Quality of Iron Castings

Khuengpukheiw R., Veerapadungphol S., Kunla V., Saikaew Charn

Archives of Foundry Engineering

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2022

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Vol. 22, iss. 4

53--64

EN

Sand molding casting has been widely used for a long time. But, one of its main drawbacks is that surface quality of the castings is not good enough for some applications. The purposes of this research were to investigate the effect of addition of sawdust ash of rubber wood (SARW) on molding sand properties and the surface quality of iron castings and to find an appropriate level of SARW with the appropriate properties of the iron castings. The molding sand compositions for making a sand mold consisted of the recycled molding sand, bentonite, water and SARW. The percentage levels of SARW were 0%, 0.1%, 0.2%, 0.3% and 0.4%. The different proportions of molding sand samples were investigated for the molding sand properties including permeability, compression strength and hardness. The results showed that addition of SARW had an effect on the molding sand properties. The appropriate percentage proportion of molding sand was obtained at 95.8% recycled molding sand, 0.8% bentonite, 3% water and 0.4% SARW. There were statistically significant differences of mean surface roughness and hardness values of the iron castings made from molding sand samples without SARW addition and the appropriate percentage proportion of molding sand. In addition, the average surface roughness value of the iron castings made from the sand mold with the appropriate percentage proportion of molding sand was ~40% lower than those of the iron castings made from molding sand samples without SARW addition.

9

The influence of biomaterial in the binder composition on the quality of reclaim from furan no-bake sands

Major-Gabryś Katarzyna, Hosadyna-Kondracka Małgorzata, Skrzyński Mateusz, Stachurek Iwona

Archives of Civil Engineering

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2022

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Vol. 68, nr 4

163--177

EN

The aim of this paper is to determine the influence of biomaterial in the binder composition on the quality of reclaim from furan no-bake sands. The biomaterial is introduced into the moulding sand in order to accelerate the biodegradation of post-regeneration dust and thus to reduce the amount of harmful waste from foundries in landfills. This addition, however, can’t deteriorate the technological properties of the moulding sand, including its ability to mechanical regeneration. Chemically bonded moulding sands are characterized by high ability to mechanical regeneration, which reduces the consumption of the raw material and costs related to their transport and storage. A side effect of the regeneration process is the formation of a large amount of post-regeneration dusts. According to the tendencies observed in recent years, moulding processes must meet high requirements connected to environmental protection including problems related to the disposal of generated wastes. A partial replacement of synthetic binding materials with biomaterials may be one of scientific research directions on the production of innovative foundry moulding and core sands. The conducted regeneration tests presented in this paper initially proved that biomaterial slightly decreases the quality of reclaim from moulding sand with its addition. However, its ability to regeneration increases with time of the process. In previous research authors tested biodegradability of the dust remaining after the regeneration process. The tests proved that moulding sand with biomaterial added at the stage of the production process is characterized by about three times better biodegradability than the same moulding sand without additive.

PL

Tematem niniejszej pracy jest określenie wpływu dodatku biomateriału (PCL) do spoiwa na jakość regeneratu z samoutwardzalnych mas furanowych. Zadaniem biomateriału jest przyspieszenie biodegradacji pyłów poregeneracyjnych i tym samym doprowadzenie do zredukowania na składowiskach ilości szkodliwych odpadów pochodzących z odlewni. Dodatek ten nie może jednak pogarszać właściwości technologicznych masy, w tym jej zdolności do regeneracji mechanicznej. Autorzy przeprowadzili proces regeneracji mechanicznej, a następnie badaniom poddali regeneraty z mas formierskich utwardzanych chemicznie przeznaczonych do produkcji wielkogabarytowych odlewów żeliwnych. Odlewy żeliwne znajdują szerokie zastosowanie w motoryzacji, transporcie morskim i kolejowym, w energetyce, rolnictwie oraz budownictwie. Produkcja odlewu wielkogabarytowego o złożonym kształcie, charakteryzującego się wysoką jakością przy zachowaniu wymaganych właściwości użytkowych, obejmuje wiele etapów procesu produkcyjnego. Jednym z nich jest odpowiedni dobór technologii mas formierskich i rdzeniowych. Masy formierskie i rdzeniowe wykorzystywane są do produkcji odlewów w około 80% wszystkich odlewni. Największą ilość odpadów wytwarzanych w odlewniach stanowi zużyta masa formierska / rdzeniowa i sięga ona czasem nawet 90%. Przyjmuje się, że średnio z 1 Mg odlewów powstaje 0,6-1,0 Mg zużytej masy [4, 5], a według [2] do wyprodukowania 1 kg odlewu potrzeba około 4 kg masy formierskiej. Światowa produkcja odlewów wynosi około 100 mln Mg [2, 6], w tym odlewy żeliwne w masach formierskich utwardzanych chemicznie w ilości 30 mln Mg, co przy założeniu stopnia regeneracji na poziomie 40-50% daje 15-18 mln Mg zużytego piasku [4]. Prezentowany w pracy temat poświęcony jest materiałom pochodzącym z procesu odlewania do form piaskowych wykonanych z piasku kwarcowego ze spoiwem organicznym na bazie żywicy modyfikowanej alkoholem furfurylowym, utwardzanej mieszaniną kwasów zawierających siarkę.

10

Research on Assessment of the Applicability of Malted Barley Binder in Moulding Sand Technology

Samociuk Bartłomiej, Gal B., Nowak D.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 1

74--80

EN

The foundry industry is looking for solutions that improve the quality of the finished product and solutions that reduce the negative impact of the industry on the natural environment [26]. This process leads to work on the use of new or previously unused materials for binders. Organic and inorganic foundry binders are replaced by renewable materials of plant origin to meet the requirements of both the foundry customers and the environmental and health and safety regulations. The aim of this work was to identify the applicability of renewable and organic malted barley binder in moulding sand technology. The influence of the malt binder content on dry tensile strength, dry bending strength, dry permeability, dry wear resistance and flowability were evaluated. The results show that the malted barley binder can be self contained material binding the high-silica sand grains. Selected mechanical properties of moulding sands were found to increase with an increase in binder content. It was observed that malted barley binder creates smooth bonding bridges between high-silica sand grains.

11

Zastosowanie biodegradowalnego polilaktydu PLA jako spoiwa do mas formierskich stosowanych w odlewnictwie

Tryznowski Mariusz, Soroczyński Artur

Przemysł Chemiczny

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2020

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T. 99, nr 10

1552--1555

PL

Zbadano przydatność polilaktydu (PLA) jako spoiwa do wielokrotnego stosowania do mas formierskich wykorzystywanych w procesach odlewniczych. PLA otrzymano z dużą wydajnością (71%) przez polikondensację laktydu. Masy formierskie z 2-proc. zawartością spoiwa uzyskano w wyniku odparowania chloroformowego roztworu PLA. Zbadano wytrzymałość na rozciąganie mas formierskich po ich wielokrotnym zawracaniu. Masy formierskie z 2-proc. zawartością PLA jako spoiwem, stapiane w wysokiej temp. 325°C można było zawracać nawet 13-krotnie, otrzymując masy charakteryzujące się dobrą jakością.

EN

Polylactide (PLA) was used as a binder for recycled molding sands in foundry processes. PLA was produced by lactide polycondensation with a high efficiency (71%). The molding sands with 2% binder content were prepd. by evaporating the solvent from CHCl3 soln. of PLA. The PLA-contg. molding sands cured at 325°C were successfully recycled up to 13 times.

12

Utwardzane mikrofalowo masy formierskie ze spoiwami nieorganicznymi przeznaczone do odlewania ablacyjnego

Puzio Sabina, Kamińska Jadwiga, Angrecki Michał, Hosadyna-Kondracka Małgorzata, Major-Gabryś Katarzyna

Przegląd Odlewnictwa

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2019

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Vol. 69, nr 5-6

114--120

PL

Celem niniejszej pracy jest wykazanie możliwości zastosowania proekologicznych mas z uwodnionym krzemianem sodu na formy do odlewania ablacyjnego. Technologia odlewania ablacyjnego przeznaczona jest przede wszystkim do wykonywania odlewów w formach piaskowych o zróżnicowanej grubości ścianki i skomplikowanych kształtach. W ramach niniejszej pracy przedstawiono wpływ zawartości spoiwa oraz czasu utwardzania na wytrzymałość na zginanie Rg mas formierskich ze spoiwami na bazie uwodnionego krzemianu sodu utwardzanych w technologii utwardzania mikrofalowego. Celem badań jest opracowanie optymalnego składu mas, który zapewni wytrzymałość niezbędną do wytworzenie formy do przeprowadzenia procesu odlewania ablacyjnego. Zastosowana mas musi jednocześnie zagwarantować podatność formy na destrukcyjne działanie medium ablacyjnego, którym jest woda. Przeprowadzone badania wykazały, że utwardzanie mikrofalowe zapewnia uzyskanie zadowalających wytrzymałości przy niskiej zawartości spoiwa w masie.

EN

The aim of this work is to demonstrate the possibility of using Environmentally friendIy molding sands with hydrostated sodium silicate for ablation casting molds. The ablation casting technology is intended primarily for making casts in sand molds with diversified wall thickness and complex shapes. This paper presents the effect of binder content and curing time on the bending strength Rg of molding sands with binders based on hydrated sodium silicate hardened in microwave curing technology. The aim of the research is to develop an optimal molding sand composition that will provide the strength necessary to form a mold for carrying out the ablative casting process. the applied sands must simultaneously guarantee the susceptibility of the mold to the destructive action of the ablative medium, which is water. The tests have shown that microwave curing provides satisfactory strengths with low binder content.

13

Multiparameter Assessment of the Gas Forming Tendency of Foundry Sands with Alkyd Resins

Mocek J.

Archives of Foundry Engineering

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2019

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iss. 2

41--48

EN

Gas atmosphere at the sand mould/cast alloy interface determines the quality of the casting obtained. Therefore the aim of this study was to measure and evaluate the gas forming tendency of selected moulding sands with alkyd resins. During direct and indirect gas measurements, the kinetics of gas evolution was recorded as a function of the temperature of the sand mixture undergoing the process of thermal destruction. The content of hydrogen and oxygen was continuously monitored to establish the type of the atmosphere created by the evolved gases (oxidizing/reducing). The existing research methodology [1, 7, 8] has been extended to include pressure-assisted technique of indirect measurement of the gas evolution rate. For this part of the studies, a new concept of the measurement was designed and tested. This article presents the results of measurements and compares gas emissions from two sand mixtures containing alkyd resins known under the trade name SL and SL2002, in which the polymerization process is initiated with isocyanate. Studies of the gas forming tendency were carried out by three methods on three test stands to record the gas evolution kinetics and evaluate the risk of gas formation in a moulding or core sand. Proprietary methods for indirect evaluation of the gas forming tendency have demonstrated a number of beneficial aspects, mainly due to the ability to record the quantity and composition of the evolved gases in real time and under stable and reproducible measurement conditions. Direct measurement of gas evolution rate from the tested sands during cast iron pouring process enables a comparison of the results with the results obtained by indirect methods.

14

Thermally Hardened Moulding and Core Sands with Hydrated Sodium Silicate Designed for Al Alloy Castings

Major-Gabryś K. A., Grabarczyk A. P., Dobosz S. M.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 3

132--137

EN

The necessity of obtaining high quality castings forces both researchers and producers to undertake research in the field of moulding sands. The key is to obtain moulding and core sands which will ensure relevant technological parameters along with high environmental standards. The most important group in this research constitutes of moulding sands with hydrated sodium silicate. The aim of the article is to propose optimized parameters of hardening process of moulding sands with hydrated sodium silicate prepared in warm-box technology. This work focuses on mechanical and thermal deformation of moulding sands with hydrated sodium silicate and inorganic additives prepared in warm-box technology. Tested moulding sands were hardened in the temperature of 140ºC for different time periods. Bending strength, thermal deformation and thermal degradation was tested. Chosen parameters were tested immediately after hardening and after 1h of cooling. Conducted research proved that it is possible to eliminate inorganic additives from moulding sands compositions. Moulding sands without additives have good enough strength properties and their economic and ecological character is improved.

15

Thermal Deformation of Moulding and Core Sands with an Inorganic Binder Containing a Relaxation Additive

Bobrowski A., Drożyński D., Jakubski J., Szumera M., Kaczmarska K., Grabowska B.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 4

93--98

EN

The paper presents the results of an investigation of the thermal deformation of moulding sands with an inorganic (geopolymer) binder with a relaxation additive, whose main task is to reduce the final (residual) strength and improves knocking-out properties of moulding sand. The moulding sand without a relaxation additive was the reference point. The research was carried out using the hot-distortion method (DMA apparatus from Multiserw-Morek). The results were combined with linear deformation studies with determination of the linear expansion factor (Netzsch DIL 402C dilatometer). The study showed that the introduction of relaxation additive has a positive effect on the thermal stability of moulding sand by limiting the measured deformation value, in relation to the moulding sand without additive. In addition, a relaxation additive slightly changes the course of the dilatometric curve. Change in the linear dimension of the moulding sand sample with the relaxation additive differs by only 0.05%, in comparison to the moulding sand without additive.

16

The Tendency of Moulding Sands to Generate Core Cracks

Grabarczyk A., Dobosz S. M., Kusiński J., Major-Gabryś K.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 1

157--161

EN

The constant growth of foundry modernization, mechanization and automation is followed with growing requirements for the quality and parameters of both moulding and core sands. Due to this changes it is necessary to widen the requirements for the parameters used for their quality evaluation by widening the testing of the moulding and core sands with the measurement of their resistance to mechanical deformation (further called elasticity). Following article covers measurements of this parameter in chosen moulding and core sands with different types of binders. It focuses on the differences in elasticity, bending strength and type of bond destruction (adhesive/cohesive) between different mixtures, and its connection to the applied bonding agent. Moulding and cores sands on which the most focus is placed on are primarily the self-hardening moulding sands with organic and inorganic binders, belonging to the group of universal applications (used as both moulding and core sands) and mixtures used in cold-box technology.

17

The Influence of Selected Water and Alcohol Based Coatings on Bending Strength of Foundry Moulds and Cores Manufactured in Furan Technology

Romelczyk R., Przyszlak N., Siodmok B., Dorula J., Studnicki A.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 2

169--172

EN

The subject of this paper was to compare the influence of selected coatings on bending strength of moulds and cores manufactured in a furan technology. In a range of study, there were used three kinds of coatings - water based coating and two kind of alcohol based coating manufactured by FOSECO. Coating were applicated by brush, overpouring/flow and spraying. For each application method, there were realized different kind of drying- at ambient temperature, in a furnace and by burning. Physicochemical properties of coatings were such selected to accommodate them to the application method and type of coating. Based on the conducted studies it was observed that for water based coating application method doesn’t have an important influence on bending strength and it is necessary to optimize the time and temperature of drying to achieve better results of bending strength. For alcohol based coatings, drying by burning causes significant deterioration of bending strength of the mould and core and drying process at ambient allows to obtain high bending strength of mould/cores in regard to time of drying.

18

Research on the Energy of Destruction of Bindings of a Core and Moulding Sand Based on Quartz Sand Grains

Dańko R., Dajczer G.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 1

19--22

EN

In the knock-out process, as well as in the preliminary phase of moulding sand reclamation, the issue of energy demand for the process of crushing used sand agglutinations, preferably to single grains, is particularly important. At present, numerical values of moulding sand impact resistance, which would allow energy-related aspects of this process to be forecast, are not known, as such research has not been carried out. It seems that impact resistance tested on very small cross-section samples, which allows us to very precisely reveal some unique features of a moulding sand with organic and inorganic binders, is an important parameter, which so far has not been taken into account for evaluation of mechanical properties of moulding sands. Preliminary attempts to determine impact resistance of moulding sands have been carried out as part of own research of the author. The conducted investigations aimed at determining the relationships between the obtained values of tensile strength and impact resistance of moulding sands. In addition, the effect of holding samples at temperatures of 100oC, 200oC, 300oC on the value of impact resistance was determined, both for sands made with fresh and with reclaimed sand grains.

19

Moulding Sand with Inorganic Cordis Binder for Ablation Casting

Hosadyna-Kondracka M., Major-Gabryś K., Kamińska J., Grabarczyk A., Angrecki M.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 4

110--115

EN

The essence of ablation casting technology consists in pouring castings in single-use moulds made from the mixture of sand and a water-soluble binder. After pouring the mould with liquid metal, while the casting is still solidifying, the mould destruction (washing out, erosion) takes place using a stream of cooling medium, which in this case is water. This paper focuses on the selection of moulding sands with hydrated sodium silicate for moulds used in the ablation casting. The research is based on the use of Cordis binder produced by the Hüttenes-Albertus Company. It is a new-generation inorganic binder based on hydrated sodium silicate. Its hardening takes place under the effect of high temperature. As part of the research, loose moulding mixtures based on the silica sand with different content of Cordis binder and special Anorgit additive were prepared. The reference material was sand mixture without the additive. The review of literature data and the results of own studies have shown that moulding sand with hydrated sodium silicate hardened by dehydration is characterized by sufficient strength properties to be used in the ablation casting process. Additionally, at the Foundry Research Institute in Krakow, preliminary semi-industrial tests were carried out on the use of Cordis sand technology in the manufacture of moulds for ablation casting. The possibility to use these sand mixtures has been confirmed in terms of both casting surface quality and sand reclamation.

20

Influence of the Reclaim Addition into the Matrix on the Hardening Process Kinetics of the Moulding Sand with Furfuryl Resin

Jamrozowicz Ł., Kolczyk J., Wojtuń P.

Archives of Foundry Engineering

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2018

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Vol. 18, iss. 1

41--46

EN

Measurements of the hardening process course of the selected self-hardening moulding sands with the reclaimed material additions to the matrix, are presented in the hereby paper. Moulding sands were produced on the „Szczakowa” sand (of the Sibelco Company) as the matrix of the main fraction FG 0,40/0,32/0,20, while the reclaim was added to it in amounts of 20, 50 and 70%. Regeneration was performed with a horizontal mechanical regenerator capacity of 10 t/h. In addition, two moulding sands, one on the fresh sand matrix another on the reclaimed matrix, were prepared for comparison. Highly-fluid urea-furfuryl resin was used as a binder, while paratoluensulphonic acid as a hardener. During investigations the hardening process course was determined, it means the wave velocity change in time: cL = f(t). The hardening process kinetics was also assessed (dClx/dt = f(t)). Investigations were carried out on the research stand for ultrasound tests. In addition strength tests were performed.